Originally Posted by Lefty78
Haas has switched to 16x19
Wawrinka used to use 18x20. So did Dimitrov.
Haas is actually back to an 18x20 as of a few days ago when he lost to Youzhny at the China Open in Beijing (although I think he outplayed Youzhny, just had some calls go against him and lost a couple key points). Here are some pictures I took. Pretty easy to see it's a PT57a 18x20 in IG paint.
FYI, if you can't read it, the pro stock code in the throat of his racket is "C091101"